Disclosed are compositions of ethylene and (meth)acrylic acid and ester elastomeric copolymers or of (meth)acrylic ester elastomeric copolymers with polylactones and certain polyethers. These compositions have improved massing resistance in the uncured state and/or improved low temperature properties in the cured or uncured state. The polylactones or polyethers are preferably at least partially grafted to the elastomeric copolymers.
Copolymers of ethylene and (meth)acrylic monomers, such as alkyl acrylates or methacrylates and acrylic or methacrylic acids, are well known items of commerce. They may broadly be divided into two categories, thermoplastics and elastomers. Most often the former contain relatively high amounts of ethylene, giving them crystallinity derived from ethylene sequences in the polymer. The latter tend to have relatively higher amounts of the (meth)acrylic monomers to break up the ethylene crystallinity, which often results in an elastomeric polymer. As is well known, thermoplastics and elastomers often have differing uses, and differing problems associated with them.
For example, because of their crystallinity and/or glassy natures, thermoplastics may be readily formed into pellets which hold their shape. However, uncured (unvulcanized) elastomers often have the problem of slowly flowing and agglomerating into one (often large) mass, so pellets of elastomers, an often desired product form, may be difficult to preserve in a package. One way of preserving elastomers as pellets is to coat the pellet surfaces with a so-called parting agent. With some elastomers which do not flow readily this may work, but for others an excessive amount of parting agent may be needed, or the parting agent will not prevent massing when used in almost any amount.
In most instances it is desirable that the elastomer stay flexible over as wide a temperature range as possible, particularly lower temperatures, where eventually elastomers become stiff and sometimes brittle. This is not a problem with thermoplastics which are supposed to be stiff. Thus methods for preventing massing and/or improving the low temperature properties of elastomers are commercially valuable.
Various thermoplastics made from ethylene and (meth)acrylic monomers have been reacted (grafted) and/or blended with poly(ethylene glycols), poly(propylene glycols) or polyesters, see for instance British Patent 936,732, U.S. Pat. Nos. 5,106,909, and 5,321,088, and World Patent Application 91/02767. None of these references specifically refer to the use of elastomeric ethylene co-polymers.
U.S. Pat. No. 3,637,544 discloses the mixing of various elastomers containing xe2x80x9cethylenic unsaturationxe2x80x9d with polylactones such as polycaprolactones. No mention is made of elastomeric ethylene/(meth)acrylic copolymers.
This invention concerns a composition, comprising:
(a) an elastomeric first polymer consisting essentially of about 10 to about 80 mole percent of ethylene, about 10 or more mole percent of 
xe2x80x83and up to about 20 mole percent, total, of one or more other polymerizable olefins; and
(b) one or more second polymers chosen from the group consisting of poly(ethylene ethers), poly(1,2-propylene ethers) and polylactones;
wherein:
each R1 is independently methyl or hydrogen; and
each R2 is independently hydrogen, hydrocarbyl or substituted hydrocarbyl;
and provided that when said second polymer is a polylactone it is present as a separate polymer from said first polymer, and/or is grafted to said first polymer, and when said second polymer is said polyethylene ether) or said polypropylene ether) at least some of said second polymer is grafted to said first polymer.
Further disclosed is a second composition which is an elastomeric first polymer consisting essentially of about 60 or more mole percent of: 
and up to about 40 mole percent of one or more comonomers selected from the group consisting of aromatic hydrocarbon olefins, acrylonitrile, olefinic monomers containing chlorine, epoxy, or carboxylic acid groups, maleic anhydride, monoalkyl and monoarylalkyl esters of maleic acid, monoalkyl and monoarylalkyl esters of fumaric acid, itaconic anhydride, monoalkyl and monoarylalkyl esters of itaconic acid, and cyanoalkyl acrylates wherein alkyl can contain 2-8 carbon atoms; and
(b) one or more second polymers chosen from the group consisting of poly(ethylene ethers), poly(1,2-propylene ethers) and polylactones;
wherein:
R1 is methyl or hydrogen; and
R2 is hydrocarbyl and/or substituted hydrocarbyl;
and provided that when said second polymer is a polylactone it is present as a separate polymer from said first polymer, and/or is grafted to said first polymer, and when said second polymer is said poly(ethylene ether) or said poly(propylene ether) at least some of said second polymer is grafted to said first polymer.
In this second composition it is preferred that R2 is independently an alkyl containing 1-8 carbon atoms, optionally substituted by one or more ether oxygens. It is also preferred that R1 is hydrogen and each R2 is independently selected from the group consisting of ethyl, butyl, methoxyethyl, ethoxyethyl, and mixtures thereof, with a proviso that at least 50 mol. % of the R2 groups be ethyl, butyl or a combination thereof. A preferred comonomer is acrylonitrile.
Herein certain terms are used, and they are defined below.
By hydrocarbyl is meant a univalent radical containing only carbon and hydrogen. Unless otherwise specified it is preferred that it contain 1 to 30 carbon atoms.
By substituted hydrocarbyl is meant hydrocarbyl containing one or more substituents (functional groups) which do not interfere with (as appropriate) amidation, transesterification and crosslinking. Useful substituents include oxo (keto), halo, ether [which sometimes could be considered (substituted) hydrocarbyloxy groups] and thioether. Unless otherwise specified it is preferred that it contain 1 to 30 carbon atoms.
By a polymerizable olefin is meant an olefin which may copolymerize with ethylene and (I) under the polymerization conditions used to form the polymer.
By olefinic double bond is meant a carbon-carbon double bond which is not part of an aromatic ring.
By an (meth)acrylic compound is meant a compound of formula (I).
By a dipolymer is meant a copolymer containing repeat units derived from two monomers.
By a polyether is meant an organic group which contains two or more ether linkages.
By grafting is meant forming an attachment between a first polymer and a second polymer. It is preferred that the attachment contains esters, amide, imide or carbon-carbon bonds.
By elastomeric or an elastomer is meant that the heat of fusion of any polymer crystallites present with a melting point (Tm) of 50xc2x0 C. or more is less than 5 J/g, more preferably less than about 2 J/g, and preferably no polymeric crystallites are present at 25xc2x0 C. (by ASTM D3451), and that the glass transition temperature (Tg) of the polymer is less than about 50xc2x0 C., more preferably less than about 20xc2x0 C., and especially preferably less than about 0xc2x0 C. The Tm and heat of fusion of the polymer are determined by ASTM method D3451 at a heating rate of 10xc2x0 C./min and the Tm is taken as the peak of the melting endotherm, while the Tg of the polymer is determined using ASTM Method E1356 at a heating rate of 10xc2x0 C./min, taking the midpoint temperature as the Tg. Both of these are determined on a second heating of the polymer.
Preferably the first polymer used in the present invention is a copolymer of ethylene and (I) [more than one species of (I) may be present], or of ethylene and (I) and the monoethyl ester of maleic or fumaric acids or maleic anhydride. In (I) it is preferred that R1 is hydrogen and/or R2 is hydrocarbyl, more preferably alkyl containing 1 to 6 carbon atoms, and especially preferably methyl [when R1 is hydrogen and R2 is methyl, (I) is methyl acrylate]. A particularly preferred first polymer is ethylene/methyl acrylate dipolymer containing about 13 to about 46 mole percent of methyl acrylate. Specific useful monomers (I) are the methyl, ethyl, propyl, n-butyl I-butyl esters of methacrylic or acrylic acids, more preferably acrylic acid.
Useful polymerizable olefins for the first polymer include maleic anhydride, maleic acid and any of its half acid esters or diesters, particularly its methyl or ethyl half acid esters, fumaric acid and any of its half acid esters or diesters, particularly its methyl or ethyl half acid esters, styrene, xcex1-methylstyrene, and substituted styrenes. For preparation of polyether grafts using amidation reactions, maleic anhydride or the half acid-ester of maleic or fumaric acid is preferred as a comonomer. Especially preferred is the monoethyl ester.
The second polymer is (one or more of) poly(ethylene ether), poly(1,2-propylene ether) and/or a polylactone. When the second polymer is a polylactone it may be present as a xe2x80x9cfreexe2x80x9d polymer in its own right, and/or it may be grafted onto the first polymer. Grafting may be carried out by any method known in the art. For example, a polylactone having at least one hydroxyl end may be reacted with a carboxyl group on the first polymer chain (for instance derived from acrylic acid of methacrylic acid in which R2 is hydrogen) to form an ester thereby grafting the polylactone to the first polymer, or when R2 is hydrocarbyl or substituted hydrocarbyl that ester may be transesterified with the polylactone also resulting in grafting of the polylactone. The polylactone may also be grafted onto the first polymer by a free radical process by mixing the first and second polymers with a free radical source, such as a peroxide, and generating free radicals by heating the mixture, thereby resulting in grafting of the polylactone onto the first polymer. It is preferred that at least 5 mole percent, more preferably at least 10 mole percent, and especially preferably at least 20 mole percent of the polylactone be grafted to the first polymer.
The presence of the polylactone improves the massing resistance of the polymer. When this is an improvement sought by addition of the polylactone, it is preferred that the polylactone (by itself, before blending and/or grafting) be semicrystalline at room temperature, that is have a melting point of  greater than 25xc2x0 C. with a heat of fusion of at least 5 J/g, and more preferably have a melting point  greater than 45xc2x0 C. with a heat of fusion of at least 25 J/g.
If at least some of the polylactone is to be grafted by transesterification or esterification it is preferred that it have an Mn (number average molecular weight) of about 1,000 to about 20,000, more preferably about 2,000 to about 15,000. If the polylactone is to be grafted using peroxide, or not grafted at all, it is preferred that the Mn is about 10,000 to about 100,000, more preferably about 30,000 to about 50,000. If polylactone of the desired Mn is not available directly, it can be made in situ by equilibrating appropriate amounts of two polylactones with differing Mn""s, or by partially depolymerizing a higher Mn polylactone with a diol. This in situ generation of the desired Mn is included within the definition of addition of a desired Mn.
The polylactone may also be used to lower the measured Tg of the first polymer, thereby improving the low temperature properties of the composition. When used for this purpose, alone, the Mn of the polylactone is not important, nor is whether the polylactone is grafted. However ungrafted low Mn polylactone may be easily removed from the composition (for example by volatilization or extraction) so the use of ungrafted very low Mn polylactone may not be desirable. When any polylactone is used it is preferred that at least some of it is grafted to the first polymer.
It is preferred that about 2 to about 20 percent by weight of the polylactone, based on the amount of first polymer present, be present in the composition, preferably about 3 to about 15 percent. A preferred polylactone is poly(xcex5-caprolactone).
The second polymer may also be a poly(ethylene ether) or a poly(1,2-propylene ether), collectively herein polyether. By a poly(ethylene ether) is meant a group or molecule that contains two or more repeat units xe2x80x94(CH2CH2O)xe2x80x94 and by a poly(1,2-propylene ether) is meant a group or molecule that contains two or more repeat units xe2x80x94(CH(CH3)CH2O)xe2x80x94. Also within the meaning of poly(ethylene ether) and poly(1,2-propylene ether) is a group or molecule containing the repeat units xe2x80x94(CH2CH2O)mxe2x80x94(CH(CH3)CH2O)nxe2x80x94 wherein m and n are both independently an integer of at least one. Poly(ethylene ether) is a preferred polyether. If n is xe2x89xa72 the polyether may be considered a poly(1,2-propylene ether), and if m is xe2x89xa72 the polyether may be considered a poly(ethylene ether). Thus, a single polymer may be both a poly(ethylene ether) and a poly(1,2-propylene ether). It is preferred that at least 5 mole percent, more preferably at least 10 mole percent, especially preferably at least 20 mole percent and very preferably at least 40 mole percent of the polyether present is grafted to the first polymer.
The polyether herein may lower the Tg of the first polymer and/or improve the massing resistance of the composition. If lowering of the Tg is the only goal of adding the polyether, the polyether may be of relatively low molecular weight for example a diether, triether or tetraether derived from compounds such as diethylene glycol, triethylene glycol or tetraethylene glycol, respectively. If improved massing resistance is desired, the polyether should preferably be of high enough molecular weight to be semicrystalline. For poly(ethylene ethers) for this purpose, an Mn of about 1500 or more is preferred, more preferably about 2000 or more. In some instances, for optimal grafting and massing resistance, it is preferred that there be a lower-MW component of Mn about 300 to 1000 for grafting and a higher-MW component of Mn about 1500 or more for massing-resistance. For purposes of grafting to lower the Tg of the elastomeric ethylene copolymer, an Mn of about 300-2000 is preferred for the poly(ethylene ethers), more preferably 300-1000, and most preferably 300-750. If the polyether is of Mn greater than 300, it is preferred that about 15-60% by weight of the total polyether (one or more polyether components) in the composition be grafted.
For lower molecular weight polyethers, up to a molecular weight of about 300, it is preferred that a relatively high percentage of the polyether present be grafted to prevent loss of the polyether through volatilization and/or extraction. For the lower molecular weight polyethers the fraction of the added polyether which is grafted (by weight) is preferably about 30-99%, more preferably 30-75%. During processing, some of the ungrafted polyether can be vented from the mixer (for instance, extruder). It is preferred that the amount of ungrafted, low-MW polyether, after such processing, amount to less than about 10-20% of the total polyether left in the product, more preferably 5-10% or lower. The amount of ungrafted polyether (and polylactone) can be determined by extraction of the ungrafted polyether and determination (for example by NMR spectroscopy) of the amount of polyether which is unextracted from the composition.
Preferably the total amount of polyether in the composition will be about 2 to about 20 weight percent of the first polymer present, more preferably about 5 to about 15 percent, and especially preferably about 5 to about 10 percent.
The second polymers herein may act as anti-massing agents and/or lower the Tg of the first polymer. Although not wishing to be bound by theory, it is believed that the second polymers are effective to lower the Tg because they are at least partially miscible with the first polymer. Such miscibility, even partial miscibility, of polymers is unusual. It is believed that the second polymers act especially well as antimassing agents when they themselves are semicrystalline at ambient temperature and preferably have some miscibility with the first polymer.
Grafting of the second polymer onto the first polymer may be carried out in similar ways for both the polyethers and polylactones. If there is a hydroxyl end on the second polymer it may be grafted to a carboxyl group on the first polymer by esterification, or to an ester group on the first polymer by transesterification. If a polylactone is used, during these reactions the polylactone itself may undergo esterification and/or transesterification reactions to change its molecular weight and/or molecular weight distribution. It will be understood by the artisan that if the second polymer has hydroxyl groups on both ends of the polymer it may crosslink the first polymer, which is undesirable. This is particularly true if the second polymer is of lower molecular weight. It is preferred that the second polymer be monofunctional (in the grafting reaction), especially if it is of lower molecular weight. This can easily be accomplished for example in lower molecular weight poly ether by using so-called capped polyethers. For instance instead of using triethylene glycol as the second polymer, a monoalkyl ether of triethylene glycol such as the monomethyl or monobutyl ether of triethylene glycol may be used.
Another polyether which may be grafted onto the first is a polyether which has a single terminal amine group, available for example under the tradename xe2x80x9cJeffamine(copyright)xe2x80x9d from Huntsman Corp. These polyethers, which often contain blocks of both poly(ethylene ether) and poly( 1,2-propylene ether) may be reacted with anhydride, carboxyl and/or ester containing first polymers to be attached to them through amide and/or imide groups. Similar block copolymers which graft through ester, carboxyl or hydroxyl ends on the block copolymers may also be used. Second polymers may also be grafted to the first polymer by free radical grafting, for example mixing the first and second polymers with a free radical generating agent such as a peroxide and heating to generate the free radicals.
The invention also includes a second composition whose elastomeric first polymer consists essentially of acrylate monomer units according to formula (I), and up to 40 mol-% of non-hydrocarbyl acrylate and non-ether-substituted-hydrocarbyl acrylate monomer units. In (I), preferably, R1 is hydrogen, and R2 is hydrocarbyl, more preferably, alkyl containing 1 to 8 carbon atoms optionally substituted by ether oxygen. It will be understood by one of skill in the art that the acrylate moiety of the first polymer may be a mixture of acrylate monomers; that is, not all the R2 groups in the polymer need be the same. In a preferred embodiment, the R2 groups are ethyl or butyl, or a combination of the two. It is well-known in the art to employ up to about 50 mol-% of additional acrylate monomers in combination with ethyl or butyl acrylate, to effect one or another desired modification to the properties of the resultant polymer. Preferred additional acrylate monomers include methoxy ethyl acrylate, ethoxy ethyl acrylate, and mixtures thereof.
The first polymer of this second composition may further be a copolymer of one or more acrylate monomers with up to 40 mol-% of non-hydrocarbyl acrylate and non-ether-substituted-hydrocarbyl acrylate monomers selected from the group consisting of aromatic hydrocarbon olefins, acrylonitrile, maleic anhydride, monoalkyl and monoarylalkyl esters of maleic acid, monoalkyl and monoarylalkyl esters of fumaric acid, itaconic anhydride, monoalkyl and monoarylalkyl esters of itaconic acid, cyanoalkyl acrylates wherein alkyl can contain 2-8 carbon atoms, and curesite monomers containing chlorine, epoxy, or carboxylic acid groups. Acrylonitrile, maleic anhydride, monoalkyl esters of maleic acid, monoalkyl esters of fumaric acid, itaconic anhydride, and monoalkyl esters of itaconic acid, are preferred non-hydrocarbyl acrylate and non-ether-substituted-hydrocarbyl acrylate comonomers.
Useful monomers that contain chlorine, epoxy, or carboxylic acid groups include 2-chloroethyl vinyl ether, vinyl chloroacetate, p-vinylbenzyl chloride, acrylic acid, methacrylic acid, allyl glycidyl ether, glycidyl acrylate, and glycidyl methacrylate. Useful aromatic hydrocarbon olefins include styrene, xcex1-methylstyrene, and substituted styrenes.
As for the first composition of this invention, the second polymer of the second composition may be present as a xe2x80x9cfreexe2x80x9d polymer in its own right, and/or it may be grafted onto the first polymer. Poly(ethylene ethers) and poly(1,2-propylene ethers) with single terminal amine groups are preferred second polymers of this second composition and it is preferred that, in this composition, they be substantially grafted to the polyacrylate first polymers of this composition. It is preferred that the first polymers to which they are grafted are polyacrylates that contain maleic anhydride or monoalkyl and monoarylalkyl esters of maleic acid or monoalkyl and monoarylalkyl esters of fumaric acid or itaconic anhydride or monoalkyl and monoarylalkyl esters of itaconic acid. Also included are compositions that comprise grafts of poly(ethylene ethers) and poly(1,2-propylene ethers) with single terminal amine groups to polyacrylates that contain epoxy, chlorine, and/or carboxylic acid cure sites (cure sites that can react with amines) and grafts of poly(ethylene ethers) and poly(1,2-propylene ethers) with single terminal alcohol groups to any polyacrylate, but in particular polyacrylates without carboxylic acid groups (that may retard grafting), produced by transesterification with the acrylate ester groups. Other such compositions may comprise grafts of poly(ethylene ethers) and poly(1,2-propylene ethers) with single terminal alcohol groups to any polyacrylate that contains carboxylic acid or epoxy or chlorine by esterification with the COOH or catalyzed addition to epoxy or (most difficult) etherification by displacement of chlorine.
All of these grafting reactions may be carried out in ways similar to those known in the art for the particular chemical reaction involved. For example for a transesterification reaction a typical transesterification catalyst such as an alkali metal alkoxide, a tetralkyl titanate, a tin compound such as dibutyltin dilaurate or stannous octoate, or a metal salt such as zinc acetate may be used as a catalyst. Typical amounts of catalyst, such as 0.3-3 weight percent based on total polymer may be used. The grafting reaction may be carried out in solution but is preferably done in neat molten polymer. For example the grafting reaction may be carried out in an extruder. If the second polymer is lower molecular weight, ungrafted second polymer may be removed before exiting the extruder by use of appropriate vacuum zones. Typical temperatures for this reaction are about 100-350xc2x0 C., more preferably about 180-300xc2x0 C., and especially preferably about 200-290xc2x0 C. When carrying out esterification or transesterification grafting reactions it is preferred to predry the ingredients. For instance, if an extruder is used as the reaction vessel, the ingredients (especially first and second polymers) may be predried before being added to the extruder, or may be dried in the first sections of the extruder in vacuum zones, before chemical reactions start taking place.
The compositions of the present invention may also contain other ingredients normally found in elastomers, such as fillers, pigments, reinforcing agents, antioxidants, antiozonants, curing (crosslinking) agents, processing aids, curing agents and plasticizers. Additional anti-massing agents such as octacosane may also be included, preferably in small amounts (see for instance Examples 5-8). These compositions are useful as elastomers which when uncured (uncrosslinked) have improved massing resistance and/or when cured or uncured have improved low temperature properties. These improved low temperature properties are shown by the lower glass transition temperatures (Tg""s) of the compositions. The compositions of the present invention may be cured (crosslinked) using methods normally used for such elastomers, see for instance U.S. Pat. No. 5,093,429. In some instances some of the comonomers present in relatively small amounts may act as crosslinking sites. When the second polymer which may be grafted onto the first is a polyether which has a single terminal amine group, it may also be desirable to add the polyether to the first polymer during the compounding stage, i.e. at the time when the other ingredients are added to the elastomeric composition.
In the Examples the following abbreviations are used:
DSCxe2x80x94differential scanning calorimetry
Exe2x80x94ethylene
MAxe2x80x94methyl acrylate
MAMExe2x80x94monoethyl maleate
MWxe2x80x94molecular weight
Mnxe2x80x94number average molecular weight
ODCBxe2x80x94o-dichlorobenzene
PCLxe2x80x94poly(xcex5-caprolactone)
PEGxe2x80x94poly(ethylene ether)
PEPOxe2x80x94an amine terminated block copolymer containing PEG and poly(1,2-propylene ether) blocks
Tgxe2x80x94glass transition temperature
In the Examples the following methods were used to test the polymer compositions.
In the Examples, 1H NMR spectra were measured with a Bruker AM-300 (300 MHz) instrument in perdeuterated tetrachloroethane solvent or with a 300 MHz GE spectrometer, Varian Associates Unity 400, or Varian Associates 500 MHz in CDCl3 solvent, optionally with tetramethylsilane as an internal standard. Inherent viscosities were measured in Cannon-Fenske viscometers (#75 for PCL) at 25xc2x0 C. The polymer concentration was 0.50 g/dl, primarily in toluene for PCL (0.055 g polymer in 11 ml solvent, or 0.075 g/15 ml, measured by pipette). The solutions were filtered through 0.5xcexc syringe filters. Thermal analyses were performed on a DuPont Instruments Differential Scanning Calorimeter according to the following protocol. A 10-18 mg portion of each sample in a metal container was placed in the spectrometer and kept in a nitrogen atmosphere throughout. The sample was heated from room temperature to 60xc2x0 C. at 20 degrees/min and held 2 min at 60xc2x0 C. (xe2x80x9cfirst heatxe2x80x9d). The sample was cooled with liquid nitrogen to xe2x88x92100xc2x0 C. and then heated to 60xc2x0 C. at 20 degrees/min and held 2 min at 60xc2x0 C. (xe2x80x9csecond heatxe2x80x9d). The sample was again cooled to xe2x88x92100xc2x0 C. and heated to 60xc2x0 C. at 20 degrees/min (xe2x80x9cthird heatxe2x80x9d). Transitions for the second and third heats, only, were reported. Melting points are taken as the peak of the melting endotherm, and Tg""s are taken at the midpoint of the inflection.
In the Examples unless otherwise noted melt reactions were conducted batchwise in a Brabender Plasticorder(copyright) (C. W. Brabender Instruments, Inc., South Hackensack, N.J., U.S.A.) with a Type 6 Mixer/Measuring Head with roller blades (xcx9c60 ml cavity). Scale-up runs were also performed in a Brabender Plasticorder(copyright) equipped with a 3-piece Prep Mixer(copyright) and roller blades (xcx9c350 ml cavity). The typical total charge for the Type 6 was 50 g and for the larger mixer, 250 g. The mixers were cleaned by running them with a mixture of Nordel(copyright) rubber (available from DuPont Dow Elastomers, Wilmington, Del., U.S.A.)/Bon Ami(copyright) cleanser (or polyethylene/Ajax(copyright)), followed by manual cleaning, sometimes with a wire brush. Continuous melt reactions were conducted in a twin-screw extruder described more completely in one of the examples.
Except where noted, all reagents were used as received. Tetrabutyl titanate [Ti(O-n-bu)4], 1,2,3,4-tetramethylbenzene, polyethylene glycol methyl ethers and oligoethylene glycol alkyl ethers were obtained from the Aldrich Chemical Company. o-Dichlorobenzene (ODCB), xylenes, methylene chloride (CH2Cl2), and methanol were obtained from EM Science. Isodurene (xcx9c90%) was obtained from the Fluka Chemical Corporation and toluene from Fisher Scientific. Poly-xcex5-caprolactone was obtained from either Polysciences or Union Carbide. Poly(ethylene-co-methyl acrylate) dipolymers and poly(ethylene-co-methyl acrylate-co-ethyl hydrogen maleate) terpolymers were obtained from the DuPont Company, Wilmington, Del., U.S.A. A dipolymer with 62 wt % methyl acrylate (MA) and a melt index (190xc2x0 C.) of xcx9c40 g/10 min is designated E/62MA, another with 59 wt % MA and a melt index of xcx9c8 is designated E/59MA, and a third polymer with 72 wt % MA and a melt index of xcx9c40 is designated E/72MA.
Except for Examples 1-4, the typical protocol for all reactions in both smaller and larger mixers was 2 min pre-mix of reagents, catalyst addition, and 13 min of reaction time, after start of catalyst addition. Thus, the total mixing time was 15 min.